Method for butt-welding pipes and tubing



May 12, 1942. J.. L ANDERSON 2,282,503

METHOD EQR. BUTT-WELDING PIPES AND TUBING Filed. Jan. 27,, 1940- 5Sheets-Sheet 1 ATTORNEY y 1942- J. L. ANDERSON 2,282,508 f METHOD FORBUTT-WEDDING PIPES AND TUBING Filed Jan. 27, 1940 5 Sheets-Sheet 2-lNVEN-TOR May .12, 1942. J. L. ANDERSON METHOD FOR BUTT-WELDING PIPESAND TUBING Fild Jan. 27, 1940 5 Sheets-Sheet s ATTORNEY EMS INVENTOR y1942- J. 1.. ANDERSON 2,282,508

METHOD FOR BUTT-WELDING PIPES AND TUBING Filed Jan. 27, 1940Sheets-Sheet 4 INVENTOR May 12, 1942. J. 1.. ANDERSON I METHOD FORBUTT-WELDING PIPES TUBING 1 Filed Jarif27} 1940 5 Sheets-Sheet 5INVENTOR' BY f 7 ATTORNEY Patented ay- 12, 3942 mrrnon' roanu'r'r-wammc. rims AND 'runmo James L. Anderson, Clcste'r, N. 1.,assignor to Air Reduction Company, Incorporated, New York, N. -Y., acorporation of New York Application January 21, 1940, Serial No. 315,931

(on. iii-=90 9 Claims.

This inventionrelates to methods for'buttwelding the ends of pipes ortubes.

One object of the invention is to provide an improved method forbutt-welding the ends of pipes and tubes by flames applied directly tothe separated end faces of the tubes. When welding in accordance withthe method of this invention the end faces to be joined are exposed todirectflame heating while spaced more closely than has heretofore beenthe practice, and the flames are directed against the ends in a mannerto heat both ends substantially uniformly while they are moving togetherand until they are in actual contact.

Another object of the invention is to maintain the pipe or tube endssymmetrical with respect to the heating means during the heating period,during the time that the ends are moving together, and after the facesare in contact. This symmetry is-obtained'in thepreferred embodiment ofthe invention by moving both tubes at the same rate with respect to arelatively fixed heating system.- The same result can be ob tained,however, by moving only one of the tubes but also moving the heatingsystem in the same direction at one-half the speed.

Among the advantages of this invention is the fact that the end faces tobe welded can be brought together slowly and without spatter of moltenmetal. It is not necessary that the tubes be forced together with ahammer blow in order to make the weld as in some methods of the priorart.

Another advantage of the symmetrical relation of the heating system andthe tube ends is that heating flames can be used after the weld is madeto play on the seam for smoothing any flash or reinforcement at theweld.

The tube ends are preferably heated without rotating them. This isadvantageous when the circumferential seam to be welded is betweensections having curves or semicircular bends, or

one section is secured in place and cannot be moved. In such cases it isoften impossible to rotate the tubes in av welding machine. The heatingmay be done with a special torch such as shown in my copendin'gapplication Serial No. 33,549, filed July 2'7, 1935, (Patent No.2,196,180, dated April 9, 1940), of which this application is acontinuation in part. 1

It is another feature of the invention that the heat is applied to thepipe ends by oscillating a system of heating flames back and forth alongthe circular extent of said faces in such a manner thatthe stopping andreversing at the end of eachoscillation is not always at the same place.In this way the development of hot spots on the end faces-is avoided.

Other objects, features and advantages of the invention will appear orbe pointed out as the specification proceeds. 1 p

In the accompanying drawings, forming part hereof:

Fig. 1 is a side elevation of a machine for weld ing in accordance withthe method of this invention;

Fig.'2 is a sectional view on the line 2-2 of Fig. 3;

Fig. 3 is a top plan view of the machine shown in Figs. 1 and 2;

Fig. 4 is asectional view on the line 4-4 of Figs. 1 and 3;

.Fig. 5 is an enlarged end view of. the torch shown in Figs. 3 and 4;

- Fig. '6 is a side view of the'torch illustrated in Fig.5, with a partof the torch shown in section along the line 8-8;

Figs. 7 and 8 are sectional views on the linesand 8-8 of Figs. 6 and 5,respectively:

Fig. 9 is a development along the circle 'of the jet orifices of aportion of the torch;

Fig. 10 is an enlarged side elevation of the motor and mechanism foroscillating the torch arm; and

Fig. 11 is a sectional view on the line Il -l I of I Fig. 10.

Two sections of tubing l0 and II which are to be welded together areheld in chucks l3 and II,

respectively. These chucks are supported on frames l6 and I1 secured toa common base l8. The chucks have a limited movement in their supportingframes for bringing the ends of the tubes together to 'make a weld. Byhaving both chucks movable and shifting them at the same time, theopposing end faces of the pipes can be maintained in a symmetricalrelation to the heating flames, with consequent equal intensity ofheating on both faces as they are brought to gether.

' A bracket 20 connected to the base 18 supports v a torch for heatingthe ends of the tubes l0 and II. This torch-holder and its operatingmechanism will be described more fully in the explanation of Fig. 4. Y

The frame I! carries a fixed support 22 (Fig. 2) and a movable support23. .I'hechuck It has a jaw 24 connected to the fixed support 22 by adovetail bearing which permits movement of the law 24 lengthwise of thetubes. Antifriction and thereby avoid spatter or flash.

bearings 26 retained by the jaw 24 bear against the face of the fixedsupport.

The jaw 24 is moved by a pinion 26 which meshes with a rack 29 fixed tothe jaw 24. The pinion 28 is driven from a shaft 38 through bevel gears3|.

The chuck M has a jaw 34 connected to the movable support 23 by adovetail bearing andmovable lengthwise of the tubes by rack and pinionmechanism which is driven from a bevel gear 36 on the shaft 38. bevelgear 36 turns in a bearing 31 carried by a bracket 38 depending from themovable support 23. The gear 36 slides axially on a splined portion ofthe shaft 38 when the movable support 23 slides lengthwise of the shaftand normal to the axis of the tubing to open or close the jaws of thechuck l4.

The chuck I4 is opened and closed. and is held closed under pressure, bya hydraulic motor 48 of the-cylinder and piston type. This motor issupported on bracket extensions of the frame l1, and is cozinected tothe movable support 23 by a piston rod 2.

blocks and 52 together, and movement toward the left separates them.

The construction of the chuck l4 (Fig. 1) is similar to that of thechuck l3 already described, and the jaws are moved by similar mechanismwhich is indicated by the same reference characters.

The shafts 38 are turned by cranks 44 to move the chucks l3 and I4toward each other to bring the ends of the tubes l8 and II together tomake a weld. Each of the cranks 44 is connected by a link 45 to thepiston rod 46 of a cylinder and piston hydraulic motor 41. The speed ofthese hydraulic motors can be controlled to move the ends of the tubestoward each other gradually A work-limit gauge 49 is hinged to the chuckl3 and is moved into the dotted-line position shown in Fig. 1 before thetubes are gripped by the chucks. Each tube is pushed through its chuckuntil the end of the tube abuts against the worklimit gauge 49. Thechuck jaws are then clamped against the tubes, the ends of which are incorrect position to be heated by the torch. After the tubes are grippedby the chucks, the gauge 49 is turned back into the full-line positionshown in Fig. 1.

v The torch for heating the ends of the tubes is made in two sectionswhich flt together to completely surround the tubes. The tip or burnerportion of the torch comprises a right burner block 5| and a left burnerblock 52. The burner block 5| is connected with a stock 53 held in aclamp 54 on a slide 55. This slide 55 is supported for lateral movementin a dovetail bearing 56 (Fig. l) by a frame 51.

Referring again to Figs. 3 and 4, the burner block 52 has a stockclamped to a slide 68 which is supported by and movable laterally on theframe 51. The slides 55 and 68 are moved toward and from one another toseparate the burner blocks 5| and 52 when tubes are to be placed in themachine, and to move the blocks into contact after the ends of the tubesare in position to be heated and the limit gauge 49 has been withdrawn.

The slides 55 and 68 are moved by means of a handle 62 at one end of alever 63 which is fulcrumed intermediate its ends to a bracket 64extending from the frame 51. The slide 55 is connected with the lowerend of the lever 63 by a link 66, and the slide 68 is connected with thelever 63, above its fulcrum, by a link 61. Movement of the handle 62toward the right brings the burner The frame 51 is supported by thebracket 28 (Figs. 1 and 3) on an arcuate undercut. bearing 69 on whichthe frame is free to oscillate about the axis of the tubes as a center.ing movement is imparted to the frame 51 by a motor 18 which drives acrank 1| through reduction gearing 12. The crank 1| has a pin working ina slot 13 of an arm 15 rigidly connected with the frame 51. The speed'ofthemotor 18 is regulated by a governor 16.

Figs. 5-9 show the construction of the torch. The inner face of thetorch is recessed to form a chamber 18 which surrounds the tubesadjacent I the ends to be welded. The flame jets issue from the slopingside walls of the chamber 18. A number of jet orifices 88 at spacedpoints around the torch slope in a direction to direct flame jetsagainst the end of the tube -|8, as illustrated in confine and guide theproducts of combustion and those gases moving across the surface of thetubing back of the end heat the metal adjacent the end, reducing theheat lost from the end face by conduction. Up to the time that the endsof the tubes l8 and H move into contact, a portion of the envelope gasfrom the torches enters the tubes. This is advantageous because it heatsthe inside of the tubes and the reducing action of the envelope gasesprotects the ends and inner surfaces from oxidation. 8

Jet orifices 84 (Fig. 8) open through the other sloping wall of thechamber 18 and direct flame jets against the end of the tube Grooves 15in front of the jet orifices 84 provide exhaust conduits for theenvelope gases. Air forthe combustion of the envelope gases is entrainedthrough air ducts" 86 (Fig. 9) on both sides of each jet Oxygen and fuelgas are supplied to the burner block 5| from the flces 88 open into agas chamber 88, and the orifices 84 into a gas chamber 89. The gaschambers are grooves, in the outer faces of the torch block closed byplates 98. These gas chambers 88 and 89 are connected by a cross conduit9| which communicateswith the gas conduit through the torch stock 53.The construction of the other torch block is similar and its descriptionunnecessary except to point out that the upper torch block 5| has agroove into which a tongue93 extends to hold the two sections of thetorch in perfect alinement. The gas chambers of the two sections oftorch are independent.

The burner blocks 5| and 52 and the upper portions of the torch stocksare water cooled. Cooling passages 95 in the burner blocks are suppliedwith water from pipes 96. The water outlet connection has a pipe 98connecting with a water-jacket 99 around the stock of the torch.

Figs. 10 and 11 show in detail the mechanism for oscillating the arm 15.The motor 18 is mounted on a support 8| that extends horizontally fromthe motor 18 toward the stationary bracket 28 and connects with avertically. extending slide I82 that moves in dovetail guide mem- Suchoscillatstock 53 (Fig. 6). The orithe crank H meshes with a rack I onthe stationary bracket 20. When the motor 1.0 is rotat- When the motor10 is moved upward the throw of the crank Ii produces a greater angularmovement of the arm 10 because the crank is closer to the axis ofoscillation of the arm 10. The reversing of the direction of rotationof'the motor 10 reverses the direction of movement of the crank II. Thiscombination of movements causes the oscillations of the arm 15, and thetorches that are moved by the arm, to stop at different angularpositions on successive oscillations. This produces a more evendistribution of the heat and prevents the overheating of certain pointson the pipe ends such as is liable to occur when the oscillations of theflames always stop and start back at the same point. a With theapparatus illustrated, the method of this invention is carried out asfollows:

I With the burner blocks of the torch moved apart and the limit gauge 49in the dotted-line position shown in Fig. 1, the tubes l0 and II are putin the chucks l3 and, respectively, and pushed into contact with thelimit gauge 49. The motors 40 are operated to close the chucks andfirmly clamp the tubes. The limit gauge 49 is then turned back into thfull-line position to get it out of the way of the torch, and the handle62 is moved to the right in Fig. 4 to bring the torch blocks 5! and 52together around the ends of the tubes. The friction of the slides andoperating mechanism is suflicient to hold the torch blocks together, butreleasable latching or locking means can be provided for holding thetorch sections together.

While the burner blocks direct flame jets against the ends of the tubes,the motor is operated to rock the frame 01 through diflerent angulardistances on successive oscillations as already explained. Thesemovements of the ,torch distribute the flame heating substantiallyuniformly over the entire areas of the end faces to be welded. Theoscillation is limited so as to avoid twisting of the hose through whichgas is supplied to the torch, but the angular movement is preferably notless than one-half the angular spacing of the heating flames. If thetubes are of a shape that can be rotated or oscillated, the inventioncan be carried out with stationary heating means and angularly movabletube supports.

In addition to the heating which each circle of flame jets produces inthe tube against which it is directed, the end of the other tube isheated by radiation from these flames. The loss of heat from the endfaces by conduction through the metal of the tubing is reduced by theenvelope gases which flow across both the inside and outside surfaces ofthe tubing and heat the metal back from the end faces.

The torch is allowed to heat the ends of the tubes for a definite periodof time, depending upon the type of weld to be produced. The directflame heating within a partially closed space permits a positive controlof the heating so that timing of the operation is practical. Oxygen inexcess of that'required for the primary combustion of the acetylene maybe employed to increase the heating effect of the torch in con--trolling the torch operation. ,While this heating with oxy-fuel gasflames. and particularly oxyacetylene flames. is a feature of theinvention, it should be understood that the method can be performed withordinary torches. that do not form an enclosure. It should be understoodalso that some features of the invention can be used with torches thathave their flame jets directed into the space between the confrontingfaces that are to be welded, but not toward either face. such as theflsh tail" flames of U. S. Patent 2,031,583 (Fig. 9) or German Patent402,400

- (August 15, 1924), though the flames will, of

has been described but various changes and mod-.-

course, be disposed around a circle for pine end welding.

After the ends of the tubes have been heated for a definite length oftime, depending on the type of weld desired. the motors 41 are operatedto move the chucks l3 and I I toward one another and bring the ends ofthe tubes into contact. The motors 41 can be made to operate at anydesired speed, but one of the features of the invention is that thesemotors can be controlled to move the tube ends into contact slowlyenough to avoid spatter or splash of metal when the end faces of thepipes are coated with fused metal.

The tube ends are subject to additional heating and are enveloped by theproducts of combustion during all of the time that the chucks are movingthe tubes together. This heating period must be taken into account indetermining how long a heating period to allow before starting themotors B1.

The strongest welds are made when the tube ends are brought to a stateof fusion. The heating must be performed quickly so that the faces arenot heated deeply enough to flow and any fused coating is thin andadheres to the solid metal behind it so that the end faces areselfsustaining.

If a shorter heating period is used the end faces may be partiallyfused, that is, some parts of the faces will be melted and other areasofthe faces may be still plastic or solid. With-fur.- ther reduction inthe heating time there is no fusion of the faces.

The heating time must be chosen according to the kind of weld desired,whether it is to be a weld between fused faces, or a weld made bybringing plastic surfaces together under pressure. The tubes are broughttogether by the motors 41 with at least as much pressure as is necessaryto eflect a weld.

The preferred embodiment of the invention iflcations can be made, andsome features can be. used without others without departing from theinvention as defined in'the claims.

- I'claim:

l. The method of welding together the ends of tubes which comprisesholding the tubes stationary with their end faces spaced apart butconfronting-one another, heating the end faces simultaneously by heatingflames projected directly against the surfaces of the end faces aroundtheir circumferences, moving the tubes toward one another, heating bothend faces substantially equally during the time that they are comingtogether, pressing the end faces of the tubes into contact with oneanother to weld them together, and continuing to project heating flamesagainst the tubes after the end faces are in contact to smooth anymolten metal. squeezed out from between the faces.

2. In the welding together of tube ends by projecting heating flamesdirectly against the end faces of the tubes while they are separated andthen bringing the tube ends together when they 3. The method ofbutt-welding the ends of tubes which comprises projecting heating flamesagainst the end faces of the tubes with said end faces separated andsymmetrical with respect to the heating flames, producing relativemovement of the tubes to bring said end faces into contact, andmaintaining said symmetrical relation until the end faces are in contactwith one an- -other.

4. Amethod of butt-welding the ends of tubes which method is similar tothat described in claim 3 but with the end faces heated by flamesdirected into the space between the separated end faces.

5. The method of butt-welding tube endswhich comprises projectingheating flames at an angle to the confronting end faces of the tubesand-directly against said confrontingend faces with said faces spacedfrom one another and with the heating flames distributed at angularlyspaced points around the end faces, distributing the heat over the endfaces by producing relative oscillatory movement of the heatingflamesand tube ends about the' axis of the tube ends and back and forththrough an angle at least as great as one-half the angular spacing ofthe heating flames that play against each end face. Y

6. The method of welding together sections of tubing, which comprisespositioning the sections with their end faces in confronting relationbut spaced apart, heating the end faces for welding by applying to eachof the edge faces a system of high-temperature flames at angularlyspaced regions around the faces, oscillating the flame systems angularlyback and forth about the axis of the tube sections, preventing theoccurrence of hot spots by causing successive oscillations of the flamesystems to stop and reverse at different points, and bringing the heatedend faces together to make a weld.

7. A method of welding similar to that described in claim 6 but with theend faces heated by flames directed into the space between the separatedend faces.

8. The method of welding together sections of tubing which comprisesheating the end faces of said sections while confronting but separated,applying the heat by projecting separate systems of flame jets directlyagainst the respective faces, partially enclosing both systems of flamejets, confining and guiding the products of combustion from the flamejets to cause them to pass across the surfaces of the end portions ofthe tubing sections, and bringing the heated end faces into contact tomake a weld.

9. The method of tube welding which com prises maintaining the tubeswith their end faces in spaced opposition, projecting flame jetsdirectly against the end faces at angularly spaced points around thecircumference of the end faces and projecting alternate flame jetsagainst different end faces, partially enclosing the flame jets,admitting air for combustion'of each flame jet from behind and to theside of that jet and opposite in direction to the products of combustionof the next adjacent jets on either side,

and confining and guiding the products of combustion' across the outsidesurface of the end 'portion of the tube against which that flame jet isprojected.

. JAMES L. ANDERSON.

